Concrete pump

ABSTRACT

A pump for conveying fluid aggregate-containing concrete from a hopper to the location desired including an improved valve that allows for sequentially advancing concrete from a pair of chambers by extension and withdrawal of respective pistons.

United States Patent 1 1 3,659,970 McElroy 1 51 May 2, 1972 [54] CONCRETE PUMP 2,998,781 9/1961 72 Inventor: Philip w. McElroy, 2300 Dolores Court. 3'279'382 0/1966 Pinole Calif. 94564 5/968 3,229,383 10/1966 [22] Filed: Aug. 14, 1969 3,494,295 2/1970 [211 859,233 FOREIGN PATENTS OR APPLICATIONS Related US. Application Data 453,750 9/1936 Greai Britain ..417/900 n f S N I A I 5' France [63] gggf gf gggggf er 762.896 4/1934 France ..417/900 52 us. or ..417/S16, 417/533, 417/900 Primary Examiner-William Freeh 51 1 1m. 01. ..F04b 7/00 Niamey-Townsend and Townsend [58] Field of Search "137/610, 612, 625.44; 417/347,

417/551, 532. 900 ABSTRACT A pump for conveying fluid aggregate-containing concrete [56] References Cited from a hopper to the location desired including an improved UNITED STATES PATENTS valve that allows for sequentially advancing concrete from a pair of chambers by extension and withdrawal of respective 1,413,165 4/1922 Keith ..417 532 piston, 1,755,464 4/1930 Williams.... ..l37/612 1,991,342 2/1935 Ball ,.417/531 2 Claims, 7 Drawing Figures iw llllllllllllllllia i lllli'lii Patented May 2, 1972 2 Sheets-Sheet l I i I i llIlll ITIHIIJHHHI IHIIII PH/Lh W MCEL ROY I N VENTOR.

'loumsend loumsend r I L CONCRETE PUMP This is a continuation-in-part of application Ser. No. 750,332, filed Aug. 5, 1968, now abandoned.

This invention relates to an improved apparatus for pumping dense material such as aggregate-containing concrete. More particularly, the invention is directed to an apparatus for providing a continuous flow of aggregate-containing concrete to the site desired.

Because of the highly abrasive character and low fluidity of concrete, particularly when combined with aggregate, it is necessary to employ batch operations for moving or pumping the concrete. However, batch (interrupted) delivery is not entirely satisfactory as the emplacement procedures are most advantageously accomplished when delivery of the aggregatecontaining concrete occurs at a uniform rate. At the present time, no known apparatus is entirely suitable for obtaining this objective of continuous delivery.

Broadly, the present invention is directed to an aggregatecontaining concrete-pumping apparatus utilizing a pair of synchronized displacement mechanisms that sequentially advance quantities of concrete along a pair of separate feed paths into and through a single conduit to provide a smooth, continuous flow of aggregate to the work site. The transition from the dual feed paths to the single conduit is accomplished through a unique valve unit that allows for sequential passage of the aggregate-containing concrete. In a preferred aspect, the valve structure is such that the concrete is conveyed thcrethrough, with a minimum of directional change, and without creating any substantial variations in the cross-sectional area of the path through which the concrete is being advanced. Such an arrangement has the advantage of minimizing any pressure drop within the system so that the pumping can be accomplished with a minimum of pump pressure. The vane (plate) of the valve is fabricated so as to assist in advancing concrete from either feed path into the single conduit. Thus it is arranged to be sequentially positioned in response to activation of one or the other of the displacement mechanisms and form a smooth surface segment for continuation of the respective path of advancement.

It is a primary object of this invention to provide an aggregate pumping system wherein a valve unit is disposed to alternately direct aggregate-containing concrete either from one pumping mechanism or another into a single conduit extending to the point desired for delivery of the aggregate-containing concrete. By employing a pair of pistons to alternately advance the aggregate-containing concrete from respective piston chambers to the single conduit, substantially continuous flow from the single conduit can be provided.

It is a further object of this invention to inhibit pressure drop along the path of advancement of the concrete by utilizing a generally straight path having a substantially uniform cross section throughout its length. Uniform cross section along the path of advancement of the concrete is important in avoiding a condition known as dry packing. Dry packing of concrete arises when the concrete is subjected to a high pressure that drives water from the mixture; dry packing occurs when concrete is forced from a point on the path of relatively large cross-sectional area to a point of relatively small crosssectional area. Variation in cross-sectional area is inherent in a Y connection wherein two conduits converge into one, and the present invention eliminates the adverse effects of such variation in cross-sectional area by providing a vane or plate in the Y joint that moves back and forth according to which displacement mechanism is feeding concrete to the joint. Such vane eliminates regions of large cross-sectional area, thereby avoiding dry packing.

As a feature and advantage of this invention, the elements of the apparatus include a hopper having a pair of discharge openings at the bottom thereof, each of which provides communication into a separate piston chamber. The piston chamber supports a reciprocally driven piston therein to first draw aggregate-containing concrete from the hopper into the chamber (charge stroke) and thence discharge the concrete therefrom (discharge stroke). The conduits are arranged generally parallel to each other so that they may be attached to the carriage of a conventional truck. However, it will be apparent to one skilled in this art that the conduits can be arranged at an angle such as about 30 to each other where carriage width permits such a configuration. The piston chambers both terminate in a single valve unit, as more fully described hereinafter, that allows for advancement of concrete from either piston chamber into a common conduit from where it is directed to the work site.

As another feature and advantage of this invention, the charge stroke of each piston is employed to assist in withdrawing concrete from the hopper into the respective piston chamber. A valve (plate) having a generally horizontal axis is arranged between the discharge outlet of the hopper and the piston chamber so that when the valve is closed, gravitational egress of aggregate-containing concrete from the hopper will be entirely prevented or at least minimized. Furthermore, when the valve plate is advanced to a second (open) position, the plate provides guidance for assisting in the withdrawal of concrete from the hopper.

These objects, features and advantages will be better understood and others will become apparent when reference is made to the following disclosure, especially in view of the attached drawings, wherein:

FIG. 1 is a sectional view of the apparatus of this invention taken along line 1-1 of FIG. 2 positioned on a conventional truck body;

FIG. 2 is a side elevational view partly in phantom taken along the line 2-2 of FIG. 1;

FIG. 3 is an enlarged fragmentary elevational view taken along the line 3-3 of FIG. 1;

FIG. 4 is an enlarged sectional view of the valve unit of this invention;

FIG. 5 is a schematic view illustrating the operation of the hydraulic system of this invention;

FIG. 6 is a fragmentary plan view of an alternate fon'n of the invention; and

FIG. 7 is a view taken along line 7-7 of FIG. 6 with portion broken away for clarity.

Referring now to the drawings wherein similar characters of reference represent corresponding parts in each of the several views, FIG. 1 includes truck chassis A attached to a conventional means of locomotion (not shown) and supporting concrete-pumping apparatus B. Truck chassis A is of conventional design and includes carriage l0 and pneumatic tires 12 and 12' disposed at the ends of axle 14. It will be apparent to one skilled in this art that apparatus B can be supported on any type of carriage. Pumping apparatus B includes hopper 16 including a pair of vertically arranged discharge outlets l8 and 18 extending into a generally horizontal conduit 19. In fluid communication with outlets l8 and 18' are generally horizontal piston chambers 20 and 20'. Chambers 20 and 20 are arranged so that when pistons 22 and 22', respectively, are fully advanced within chambers 20 and 20', they will abut conduit 19 generally beneath outlets l8 and 18.

Turning now to FIG. 3 wherein the portion of cylinder 19 associated with outlet 18 is shown in greater detail, there is provided a pivotally mounted hydraulically positionable baffle plate 24 secured to shaft 26 for rotation therewith. Shaft 26 is rotated through activation by link 28 and piston rod 30 that in turn is activated by hydraulic cylinder 31. When baflle 24 is pivoted out of contact with the end of aperture 18, fluid communication is provided between hopper I6 and chamber 20 as shown in phantom in FIG. 3. When bafile 24 is returned to its seated position at the lower end of discharge outlet 18, a continuous path is created to provide fluid communication from chamber 20 through conduit 19 and into conduit 32 forming one leg of V-shaped valve unit 34. In a similar manner, discharge outlet 18' is provided with plate 24, shaft 26', link 28, piston 30 and cylinder 31'. Furthermore, leg 32' of the V-shaped valve unit 34 is arranged to be in fluid communication through housing 19 (not shown) with chamber 20'. It will be apparent to one skilled in this art that pivotally mounted baffle plates 24 and 24' can be replaced by independently horizontally slidable baffle plates (not shown).

The essence of the invention is illustrated in FIG. 4 which depicts valve unit 34 including diagonally intersecting legs 32 and 32. Legs 32 and 32 are provided at their outer ends with conventional means for attaching valve unit 34 to respective of housings 19 and 19' (not shown). It is advantageous for legs 32 and 32' to be as close to parallel as is possible so that little directional change is necessitated. Thus, it is preferred that the angle between them be minimized, i.e., as little as or even less. The opposite end of valve unit 34 is provided with a single outlet conduit 36 which is also constructed so as to be attached in a conventional manner (such as with an annular bolted flange) to cylindrical conduit 37, from which the aggregate-containing concrete is directed as desired. Within valve unit 34 is positioned a generally vertical baffle plate 38 mounted for pivotal movement by rotation of shaft 40 to which baffle plate 38 is rigidly secured such as by force fitting. As shown most clearly in FIG. 1, plate 38 is driven through shaft 40, link 42 and piston rod 43 from hydraulically operated cylinder 44. Thus, when it is desired to convey concrete along leg 32 into outlet conduit 36, bafile plate 38 is positioned as illustrated in full lines in FIG. 4. When concrete flow from leg 32' is desired, baffle plate 38 is positioned in the location illustrated in phantom in FIG. 4. Bafile plate 38 is preferably of wedge-shaped cross section so that the path of concrete advancement will be most uniform. In this manner, when disposed to allow concrete flow through conduit 19, one side of plate 38 will be coplanar with a wall of leg 32 and a wall of conduit 36 while when flow from conduit 19' is desired, the other side of plate 38 will be coplanar with a wall of leg 32 and a wall of conduit 36.

In operation, hopper 16 is first filled with the desired quantity of aggregate-containing concrete. Referring to the arrows on FIGS. 1-3, the pumping apparatus is then activated as follows. Baffle plate 24' is positioned for withdrawal of concrete from hopper 16 while baffle plate 24 is retained in its seated horizontal position in outlet 18. Piston 22 is withdrawn to the position shown in FIG. 1 thereby drawing concrete through a portion of conduit 19 and into piston chamber 20. Simultaneously therewith, piston 22 is advanced to the position as shown in FIG. 1 to allow passage of concrete along leg 32 and into conduit 37. Thereafter the various positions of the pistons and baffle plates is reversed. By this it is meant that bafile plate 24' is opened, baffle plate 24 is closed, piston 22 is advanced to force the concrete occupying chamber 20' out through housing 19 into leg 32' and through outlet conduit 36 into conduit 37. Simultaneously therewith, piston 22 is withdrawn to allow chamber 20 to be filled with aggregate-containing concrete. This cycle is continuously repeated until all the concrete in hopper 16 has been advanced through valve vent 34.

Piston chambers 20 and 20' are of circular configuration as is outlet conduit 37. However, in order that baffle plates 24, 24' and 38 will properly seat in their respective openings, housing 19 and valve unit 34 are of generally rectangular cross section, and preferably square. The transition from rectangular to circular is accomplished at the end of housing 19 attached to chambers 20 and 20' and at orifice 36. A typical example of the dimensions required to accomplish a smooth transition from the circular area of flow to the square area of flow and back to the circular area of flow with a minimum of pressure drop is apparatus in which chambers 20 and 20' and delivery conduit 37 are of 8-inch diameter while valve unit 34 as well as housing 19 are about 7.09 inches square.

Referring now to FIG. 5, the various hydraulic movements necessary to sequentially advance the concrete through the apparatus are shown schematically. The hydraulic fluid is stored in a reservoir 50 and transferred when desired through pump 52 and valve 53 to the proper side of hydraulic cylinders 21,21',3l,31' and 44.

The alternate form of the invention shown in FIG. 6 includes many elements equivalent to those in the form of the embodiment of FIGS. l-4; such equivalent elements are identified in FIG. 6 by reference numerals greater by than the reference numerals identifying equivalent elements in FIGS. 1-4. A hopper 116 has outlets 118 and 118' that are in communication with conduits 132 and 132' respectively. Such conduits have a square or rectangular cross section and are formed in a generally V-shaped valve unit 134. At their righthand extremities as viewed in FIG. 6, conduits 132 and 132' communicate respectively with plunger chambers 120 and 120. Disposed in each chamber for slidable reciprocal movement therein is a piston or plunger, one such being indicated fragmentarily at 122. At the left-hand end of valve unit 134, conduits 132 and 132' converge to form an outlet opening 136 which communicates with a cylindric conduit 137 so that the concrete can be directed as desired. A pivotally movable baffie plate 138 is provided the confluence of conduits 132 and 132 to avoid variation in the cross-sectional area of the path along which the concrete is moved.

The valve arrangements associated with conduits 132 and 132' are identical and for that reason a detailed description of only one will sufiice. Conduit 132 has a planar top wall immediately above which is supported a valve plate or baffle 124. Valve plate 124 is supported for sliding movement by a guide frame structure 152 which guides the valve plate for movement between an outer open position as shown at 124 in FIG. 6 and an inner closed position as shown at 124' in the figure. Guide frame 152 at the outer extremity thereof has a cross plate 154 on which is rigidly mounted a hydraulic actuator or the like 131. The actuator includes a piston rod which is connected at its outer end to valve plate 124.

The operation of the embodiment of FIG. 6 is substantially identical to that described hereinabove with respect to FIGS. 1-5. More specifically, the valve plates 124 and 124' operate in alternation and are synchronized with the respective plungers in plunger chambers 120 and 120' and with the movement of baffle plate 138. The structure of FIG. 6 permits the construction of a machine having a vertical extent somewhat less than that of the embodiment described hereinabove and additionally permits concrete to be displaced from a plunger chamber back into the hopper as may occur when it is desired to interrupt temporarily the discharge of concrete.

Although the foregoing invention has been described in some detail by way of illustration and example for purposes of clarity of understanding, it will be understood that certain changes and modifications may be practiced within the spirit of the invention as limited only by the scope of the appended claims.

What is claimed is:

1. Apparatus for pumping concrete comprising means defining an open top hopper for containing the concrete. said hopper having first and second spaced apart discharge openings in a lower portion thereof so that concrete in said hopper is gravity biased toward said discharge openings, first and second plunger chambers below said hopper and in fluid communication with respective said discharge openings, first and second plungers reciprocally movable in respective said chambers, means for reciprocating said plungers in alternation between a loading stroke at which the plunger moves away from the discharge opening and an unloading stroke at which the plunger moves toward the discharge opening, first and second valve means interposed between respective said discharge openings and said plunger chambers for selectively interrupting flow of concrete between said hopper and said plunger chambers, means for opening respective said valves means during the loading stroke of the respective said plunger and for closing respective said valves during the unloading stroke of the respective said plunger, first and second outlet pipes extending from respective chambers for conveying concrete from said chambers during respective unloading strokes, means for efi'ecting convergence of said outlet pipes into a single discharge conduit, said convergence effecting means including a generally Y-shaped chamber having a pair of angularly spaced apart input channels communicating with respective said outlet pipes and an outlet channel, a vane havareas of the paths established when said vane is in said first position and in said second position being substantially equal to the cross-sectional areas of said first and second outlet pipes, said input channels and said outlet channel.

2. The invention of claim 1 in combination with means synchronized with said plungers for driving said vane between said first and second positions.

I i i i l 

1. Apparatus for pumping concrete comprising means defining an open top hopper for containing the concrete, said hopper having first and second spaced apart discharge openings in a lower portion thereof so that concrete in said hopper is gravity biased toward said discharge openings, first and second plunger chambers below said hopper and in fluid communication with respective said discharge openings, first and second plungers reciprocally movable in respective said chambers, means for reciprocating said plungers in alternation between a loading stroke at which the plunger moves away from the discharge opening and an unloading stroke at which the plunger moves toward the discharge opening, first and second valve means interposed between respective said discharge openings and said plunger chambers for selectively interrupting flow of concrete between said hopper and said plunger chambers, means for opening respective said valves means during the loading stroke of the respective said plunger and for closing respective said valves during the unloading stroke of the respective said plunger, first and second outlet pipes extending from respective chambers for conveying concrete from said chambers during respective unloading strokes, means for effecting convergence of said outlet pipes into a single discharge conduit, said convergence effecting means including a generally Y-shaped chamber having a pair of angularly spaced apart input channels communicating with respective said outlet pipes and an outlet channel, a vane having an upstream edge, and means for mounting said vane at the upstream edge thereof in said Y-shaped chamber for movement about an axis between said input channels and symmetrical of said outlet channel, said vane being pivotal between a first position at which communication is established from said first outlet pipe to said outlet channel and a second position at which communication is established from said second outlet pipe to said outlet channel, the cross-sectional areas of the paths established when said vane is in said first position and in said second position being substantially equal to the cross-sectional areas of said first and second outlet pipes, said input channels and said outlet channel.
 2. The invention of claim 1 in combination with means synchronized with said plungers for driving said vane between said first and second positions. 